The present disclosure relates generally to vehicle steering control systems and, more particularly, to an electric power steering system having a lane keeping function integrated therewith.
A number of vehicle systems have been devised to assist the vehicle in maintaining a central position within a driving lane. Generally, a “lane keeping” system will include a device such as a video camera that gathers information on the current position of the vehicle, along with sensors for detecting certain dynamic state variables of the vehicle. Changes in the curvature of the road path is treated as unknown disturbances. Through the use of information on the deviation of the vehicle from the center of the driving lane, as well as the dynamic state variables of the vehicle, an appropriate feedback indication is provided to the driver.
For example, the feedback indication could be in the form of an audio signal, a visual signal, and/or a haptic signal to the driver. Such a signal would alert the driver that a corrective action may be required if the driver's intent is not to deviate from the center of the driving lane. In addition to driver feedback, the lane keeping system may also be integrated within the steering system of the vehicle to provide a corrective input thereto when a path deviation is detected. However, it may not always be desirable for the lane keeping function to assume total control over the steering but rather to assist the driver in maintaining control of the vehicle's path in accordance with the driver's intent.
Conventional lane keeping systems usually employ a camera system and control system integrated with a steering system to provide a lane keeping assist torque. In addition, such systems may employ various means to evaluate the driver's intent to ascertain whether a torque input in intentional or just a deviation of the vehicle from a desired path. However, such systems are very complex, involving multiple sensor systems and utilize multiple control loops to maintain a lane keeping function. Accordingly, an assistive lane keeping system is desired that provides operator cues to assist an driver with lane keeping, yet may be configured for autonomous operation that is less complex than existing systems.